Using sketchup for level models (First game video inside)

Right now I'm trialling Sketchup as part of my asset creation pipeline, mainly as a way of quickly making rooms for further refinement (texturing, optimising etc) in blender. This week I decided to trial sketchup and see just how easily I could get it to make something usable as a game asset, first I started off by creating a floor plan.

Then with a collection of free plugins (which will be listed at the end of the article) I set about bringing my dream into reality. This was a fairly quick process, I'd say it only took me 1-2 hours (including making the floor plan. Which I didn't invest a lot of time on.)

So with this done what I spend my next 1-2 hours doing is hiding walls and removing coplanar faces. When I draw a wall that comes out of another one, the end of my second wall meets part of the face on my first wall. These two faces occupy the same space and are hidden geometries so with the goal of improving the quality of the model I set about deleting these faces.

With that done I exported as a .Obj, loaded into blender, and found the stairs about ten times bigger hovering quite far away from the room. To solve this I made the whole scene into one component essentially binding the separate parts of the model. Imported into blender and found everything was in order.

So I imported the .blend file to JMonkey to see the initial results. And my god was I surprised! The surfaces were all flickering and all the doorways seem to flicker in and out of existence. This wasn't what I'd seen in blender and it was definitely a surprise. I'd seen some flicker on the floor in some patches in blender but nothing to this extent. (unfortunately I didn't screenshot this monster).

The flicker was I found down to duplicate faces, it seemed that sketchup had overlaying faces. Now I'm no expert on the 3D assets front but any software that doubles the number of faces required seems to be a no go for me. But I expected some tweaking in blender so I selected all the vertices in edit mode and then pressed: w -> delete duplicates. Over 500 vertices were removed, so in other words things were looking pretty bad.

Imported into JMonkey. Less flicker but still flicker, and more disturbingly the doorways were still obscured. Something which I did manage to screenshot:

That rectangle on the right... That shouldn't be there.
In fact none of the black bits should

Okay. Time to google.

From my googling I found two programs: Meshlab and Netfabb basic, I used Meshlab to convert my .Obj to a .STL so I could load it into Netfabb. Netfabb seems to have quite a few uses (at least the paid for version does). But one thing it can do is take a format suited to a 3D printer (STL), and find flaws in the mesh. Things like hidden vertices, coplanar faces, inverted faces, lack of a closed volume.

And sure enough Netfabb showed the flaws that blender wouldn't:

The red parts are flaws in the mesh, and you can clearly see the doorways are filled in as well as part of the floor is red. The red floor is down to the face being upside down making the normals wrong. So I went into Sketchup and flipped the upside down faces to the right way round. But the doors. The doors were still a problem.

So I decided to take a walk around the level with the flipped faces fixed, the room did look better (slightly) but as I walked I saw something with the flickering faces. The majority of them seemed to be triangles, and then it occurred to me. I hadn't triangulated the mesh!

So I went into Sketchup and checked the triangulate mesh options on the exporter and voila:

Perfecto

So with some quick texturing in blender (Sketchup is definitely not for my texturing needs no UV unwrapping). I have my first piece of "game footage". You'll see the lighting isn't presentable yet (something I'm still to look into) and the texture seems a bit pixelated, also in the model I appear to have made rooms, corridors and doorways too narrow/small so things feel a bit claustrophobic. But that's something I'll address.

However it's exciting to have a room to walk around in instead of just a flat plane. One step closer to realising my dream!

Sketchup plugins used:

FredoScale

Cleanup

Joint Push Pull

1001bit tools

Buildedge

You can find all these from the sketchup plugin warehouse or sketchucation.